| 摘要 |
A method for fabricating a MOS transistor in a semiconductor device is disclosed. An example method subjects a surface of a semiconductor substrate to thermal oxidation to form an oxide film for forming a gate insulating film, deposits a polysilicon layer on the oxide film for forming a gate, applies a coat of photoresist onto the polysilicon layer, and performs exposure and development by using an exposure mask which defines the gate to form a photoresist pattern covering a region where the gate is to be formed. The example method also performs dry etching to remove the polysilicon layer for forming the gate and the oxide film for forming the gate insulating film, which are not protected with the photoresist pattern, to form a gate pattern, performs annealing under a nitrogen environment to form a nitrided oxide film, and forms buried lightly doped impurity ion layers on opposite sides of the gate pattern. Additionally, the example method deposits an insulating layer on the substrate to cover the gate pattern and etches back the insulating layer to expose the surface of the semiconductor substrate to form sidewall spacers, forms buried heavily doped impurity ion layers in the semiconductor substrate at exposed active regions by using the gate pattern and the sidewall spacers as an ion injection mask, and performs annealing to diffuse impurity ions for forming source/drain junctions to form lightly doped impurity diffusion regions and heavily doped impurity diffusion regions.
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